Galactic FUV Extinction Determined Using FUSE

We present an extinction analysis of sight lines selected from all
public FUSE observations of Galactic O and B stars. Over 90% of Milky
Way extinction curves sampled from IR through UV wavelengths (UV
coverage provided by IUE) conform to the CCM family of curves based on
R(V), a single parameter linked to grain size (Cardelli, Clayton, &
Mathis 1989, ApJ, 345, 245; Valencic, Clayton, & Gordon 2004, ApJ,
616, 912). The far-ultraviolet (FUV) portion of this formulation,
however, was based only on a few sight lines observed by Copernicus.
FUSE has observed a large number of diverse sight lines through the
Galaxy, and a preliminary sample including paths characterised by a wide
range of R (Sofia et al. 2005, ApJ, in press) suggests that CCM does not
predict extinction in the FUV as accurately as it does at IUE
wavelengths. We include in this poster a selection of sight lines from
among the sample we are studying in search of a more accurate FUV
extinction description.